Abstract
Purpose :
A previous study reported that suturing eyelids of rabbits induced form deprivation myopia (FDM); however, it is difficult to evaluate the effects of frequent topical treatment, e.g. eye drops, in that model. The purpose of this study was to establish the rabbit FDM model as suitable for the evaluation of frequent topical treatment. To this end, openable cover cap for FD was newly designed and evaluated in this study.
Methods :
Twelve-day-old Japanese White rabbits were assigned into 2 groups: FD with saline (n=11) and atropine (n=9). A cover cap was attached to each animal's left eye for 3 weeks and the effects of FD were evaluated by comparing it with the contralateral control eyes. Either one drop of saline or 10% atropine was applied to the FD eye once a day, starting from the initiation of cover cap wear and continuing throughout the 3 weeks. Optical axial length and refractive error were measured using A-scan ultrasound biometry and auto refract-keratometer, respectively, 3 weeks after the start of FD. After the last measruement of axial length and refractive error, rabbits were humanely euthanized, and the stiffness of strips of equatorial sclera were evaluated by tension test.
Results :
Compared with contralateral eyes, FD for 3 weeks induced the ocular elongation of 0.39±0.08 mm and myopic refractive shift of −4.49±0.81 D. In contrast, instillation of 10% atropine significantly suppressed the elongation of 0.03±0.02 mm, myopic refractive shift of +0.70±0.39 D. In addition, the scleral stiffness of FDM eyes were significantly lower than those of contralateral control eyes. Instillation of 10% atropine significantly inhibited in the weakening of sclera induced by FDM.
Conclusions :
Using the original cover cap, we established a novel rabbit FDM model that can be used for the evaluation of the effects of frequent topical treatment. The biological weakness of sclera is thought to be one of the causes of this FDM model, and the anti-myopia effects of atropine would be explained by the prevention of this.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.